Grinding wheel guard device

ABSTRACT

A grinding machine is provided with a grinding wheel guard pivotally mounted on the rear end of a grinding wheel head and a driving means is operatively connected to the grinding wheel guard for automatically raising the grinding wheel guard by pivotally rotating the same to the opposite side of the normal grinding position and for lowering the guard to its closed position, whereby the guard is readily displaced for permitting a worn grinding wheel to be replaced.

B llmted States Patent 1191 1111 3,726,048 Ota et al. 5] Apr. 10, 1973[54] GRINDING WHEEL GUARD DEVICE 1,694,340 12 1928 Weinland ..5l/268 x1,550,712 8/1925 Smith [75] Inventors 2:5 2; Tune" both of 2,011,1088/1935 Lehmann ..5l/268 y p 2,655,067 10/1953 Bechler ..51/268 x [73]Assignee: Toyoda Koki Kabushiki Kaisha,

Aichi-ken, Japan Primary Examiner-Donald G. Kelly [22] Filed: Man 11,1971 Attorney0blon, Flsher & Spnvak [21] Appl. No.: 123,223 57 ABSTRACTA grinding machine is provided with a grinding wheel Forelgn ApplwatlonPmmty Data guard pivotally mounted on the rear end of a grinding Mar.13, 1970 Japan ..45/24701 Wheel head and a driving means is operativelynected to the grinding wheel guard for automatically 52 us. c1...51/269, 51/272, 241/285 B raising the grinding wheel guard byPivotally rotating [51] Int. Cl. ..B24b 55/04 h m to h pp i i f h n rm lgrin ing [58] Field of Search ..51/268, 269, 272; position and forlowering the guard to its closed posi- 241/285 B tion, whereby the guardis readily displaced for perrnitting a worn grinding wheel to bereplaced. [56] References Cited 6 Claims, 3 Drawing Figures UNITEDSTATES PATENTS 2,368,225 l/1945 Lebermann .5l/268 X PATENTEDAPR 1 @1915SHEET 1 UF 2 Fig-1 ri ll INVENTORS HIROSHI OTA TUNEJI FUJH ORNEYBACKGROUND OF THE INVENTION The present invention relates generally togrinding machines and more particularly to a grinding wheel guard devicefor a grinding machine which is automatically upwardly opened to bedisposed on the opposite side of the normal grinding position forpermitting a worn grinding wheel to be exchanged and is subsequentlyautomatically lowered to a closed position.

Heretofore, conventional multi-wheel grinding machines for grinding suchelements as, for example, a crankshaft by means of a plurality ofgrinding wheels having relatively large diameters have been providedwith relatively large size grinding wheel guards to prevent scatteringof pieces of broken grinding wheels, such as may occur when a grindingwheel is broken, and to prevent splashing of coolant fluid used in mostgrinding operations. In such grinding machines, when it becomesnecessary to exchange one or more of the grinding wheels for another ora new one, the former cumbersome grinding wheel guards must be manuallyremoved from the original guarding position by means of lifting the sameupwardly, using a crane or the like. It should also be understood thatthese operations have been extremely dangerous because of the size ofthe guards and the complexity of the lifting operation, and that a greatamount of time was required to complete the operation.

SUMMARY OF THE INVENTION Accordingly, it is an object of the presentinvention to provide a new and improved grinding wheel guard device inwhich the grinding wheel guard is easily removed from its normalguarding position, namely the guard is automatically upwardly opened tobe disposed on the opposite side of the normal grinding position, and isreadily closed thereafter, for permitting access to the grinding wheelarea whereby a wheel may be dressed or exchanged.

Another object of the present invention is to provide a grinding wheelguard which has improved safety characteristics in its operation and issimple in construction, yet is highly effective and reliable; in.performance.

A still further object of the present invention is to provide a grindingwheel guard which may automatically be quickly and safely displaced fromand returned to its nonnal grinding wheel guarding position.

The foregoing and other objects are realized by the present inventionwhich is embodied in a grinding wheel guard for use in a grindingmachine which is pivotally mounted on the rear end of the grinding wheelhead. A reversible motor is drivingly connected with the grinding wheelguard for rotating the guard upwardly about its pivot axis to positionit on the opposite side of the normal grinding position for permittingthe grinding wheels normally covered thereby to be dressed or exchanged,and for returning the guard to its original closed, or guarding,position when a grinding operation is being carried out.

BRIEF DESCRIPTION OF THE DRAWINGS Various other objects, features andattendant advantages of the present invention willbe more fullyappreciated as the same becomes better understood from the followingdetailed description of a preferred embodiment thereof when consideredin connection with the accompanying drawings, in which like referencenumerals designate like or corresponding parts in the several views, andwherein:

FIG. 1 is a plan view of a grinding wheel guard device constructed inaccordance with the teachings of the present invention;

FIG. 2 is a sectional view taken along line II-ll of FIG. 1; and

FIG. 3 is a sectional view taken along the line IlI-III of FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION Now, with reference to theaccompanying drawings, a preferred embodiment of the present inventionwill be explained.

In FIG. 2, a grinding wheel spindle 2, having a plurality of grindingwheels 3 supported thereon in predetermined spaced relation, isrotatably mounted on a grinding wheel head 1. A grinding wheel guard orcover 8 is secured to the grinding wheel head 1 by means of clampingfixtures 13 passing through side plates 12 which are integrally formedon or suitably attached to opposite sides of the grinding wheel guard 8.An opening having a cover plate 4 pivotally disposed thereover isprovided on the upper part of the grinding wheel guard 8 for adjusting adressing device and the like positioned therebelow. At the left end ofthe grinding wheel guard 8 as viewed in FIG. 2, or the front portionthereof, there is pivotally mounted a coolant cover 5 having a coolantnozzle 6 thereon for supplying a cooling fluid between the grindingwheels 3 and a workpiece not shown.

A gear box 9 is provided on one side of the grinding wheel head 1, asshown in FIG. 1. In FIG. 3, a shaft 10 is shown being rotatablyjournaled on bearing supports in the gear box 9. The shaft 10 has aflange 10a on one end thereof which projects from the grinding wheelguard side of the gear box 9 and. is secured to a disc member 14attached to the adjacent side of the grinding wheel guard 8 through aplate 24a. The other end of the shaft 10 is secured to the bearing meansin the usual manner by a nut for preventing axial movement of the shaft10.

A worm wheel 11 is concentrically keyed to the shaft 10. Rotatablymounted on the gear box 9 through suitable bearing means, as shown inFIG. 2, and aligned perpendicular to the shaft 10 and positionedtherebelow is a worm shaft 16 having a worm 15 formed on the middleportion thereof which operatively engages the worm wheel 1 l. A sprocket17 and a hand wheel 18 are keyed to the shaft 16 at one end thereof,being positioned adjacent each other and providing means for manuallyopening and closing the grinding wheel guard 8 in the manner set forthhereinbelow.

The sprocket 17 is operatively connected with a sprocket 20 mounted onan output shaft of a driving motor 21, as shown in FIG. 3, through acontinuous drive chain 19 for driving the shaft 16. A casing 22 isfixedly mounted on the side of the grinding wheel head 1 opposite thaton which the gear box 9 is disposed. A shaft 23 is rotatably mounted inthe casing 22 through suitable bearing means. A flange 23a integrallyformed on the shaft 23 is secured to the adjacent side of the grindingwheel guard 8 through a plate 24. Furthermore, a hollow shaft 25 issecured on the upper and rear portion of the grinding wheel guard 8,being arranged parallel to the axes of the grinding wheels 3. The discplate 14 and the flange 23a are fixedly secured on respective sides ofthe hollow shaft 25 and the shafts 10 and 23 are coaxially aligned withthe hollow shaft 25. Thus, the grinding wheel guard 8 can be pivotallymoved about the axis of the hollow shaft 25, or in other words, thegrinding wheel guard 8 can be opened upwardly and rearwardly away from anormal grinding position and shut by operation of the driving motor 21or by manually turning the hand wheel 18. Limit switches 28 and 27 aresecured on the gear box 9 with a predetermined space establishedtherebetween for recognizing completion of the opening and closingmovements, respectively, of the grinding wheel guard 8 by means ofengagement therewith of a dog plate 26 mounted on the grinding wheelguard 8.

The operation of the aforedescribed preferred embodiment of the presentinvention will now be explained.

When the grinding wheels 3 have been worn to a predetermined minimumdiameter whereby an exchange with new grinding wheels is required, orwhen the grinding wheels 3 are dressed, the clamping fixtures 13 arereleased and removed. Thus, the grinding wheel guard 8 is free from itsusual clamped condition on the grinding wheel head 1. Next, the drivingmotor 21 is actuated to rotate the worm 15 on the shaft 16 through thesprockets 17 and 20 and the continuous drive chain 19. In consequence,the wonn wheel 11 mounted on the shaft 10 is rotated through the meshingengagement of the worm 15 and the worm wheel 11, whereby the grindingwheel guard 8 is upwardly rotated or opened about the axis of the hollowshaft by means of rotation of the shaft 10 which is integrally connectedwith the hollow shaft 25 until it has been retracted to its upper orfully open position which is opposite of the usual grinding position, asshown in FIG. 2 by the dotted line illustration.

When the limit switch 28 is actuated by engagement of the dog 26therewith and the full opening of the grinding wheel guard 8 isrecognized, the operation of the driving motor 21 is halted and thepivotal movement of the grinding wheel guard 8 is likewise stopped. Inthis condition, the grinding wheel spindle 2 having the worn grindingwheels 3 thereon is replaced with another spindle 2 having new grindingwheels thereon. Upon the completion of the replacement of exchange ofthe grinding wheel spindles, the driving motor 21 is reversely rotatedfor pivotally moving the grinding wheel guard 8 to the original positionthereof, or for shutting the grinding wheel guard 8, through reverserotation of the worm wheel 11. When the grinding wheel guard 8 hasreturned to its original position wherein the limit switch 27 isactuated by the dog plate 26, rotation of the driving motor 21 isstopped in response to recognition of the returning movement of thegrinding wheel guard 8. Then, the side plates 12 of the grinding wheelguard 8 are secured on the grinding wheel head 1 by means of theclamping fixtures l3, and the operation of the grinding wheel guard 8 isfully completed.

In the event the driving motor 21 is not operative because of someproblem therewith, or because of failure of the electric power supply,the hand wheel 18 may be utilized for manually opening and shutting thegrinding wheel guard 8.

It should now be apparent that the present invention provides animproved grinding wheel guard device wherein the grinding wheel guard ispivotally mounted on the rear end of a grinding wheel head and may beupwardly rotated to be disposed on the opposite side of the normalgrinding position by a suitable powered driving means, whereby thegrinding wheel guard is automatically opened. Accordingly, when aspindle which has grinding wheels thereon is to be exchanged withanother such spindle, or the dressing device and the like of theapparatus is to be adjusted, the grinding wheel guard is automaticallyretracted or opened from its original position to another position wherethe grinding wheel guard does not obstruct the aforedescribed operationwithout using a conventional crane or the like. Moreover, as a worm andworm wheel mechanism is used in the grinding wheel guard device, thegrinding wheel guard may be stopped in any position during the operationof opening or shutting the same, even if the driving means fails torotate because of trouble therewith or because of an electric powersupply failure. Thus, it should be understood that the grinding wheelguard device according to the present invention is extremely reliableand offers safety features not previously afforded by former guards.

While the invention has been described by means of a specificembodiment, it-should be understood that the novel characteristics ofthe invention may be incorporated in other structural forms withoutdeparting from the spirit and scope of the invention as defined in thefollowing claims.

What is claimed as new and desired to be secured by letters patent ofthe united states is:

1. A grinding wheel guard device for a grinding machine characterized bya grinding wheel head rotatably supporting at least one grinding wheel,comprising:

a first shaft member rotatably mounted on said grinding wheel head;

a grinding wheel guard secured to said first shaft member; and

drive means mounted on said grinding wheel head being operably connectedwith said first shaft member for moving said grinding wheel guardrelative to said grinding wheel head;

said drive means comprising a worm wheel keyed to said first shaftmember, a second shaft member rotatably mounted on said grinding wheelhead and a worm gear disposed on said second shaft member for rotationtherewith being operably engaged with said worm wheel for causing saidfirst shaft member supporting said grinding wheel guard to rotate,whereby pivotable movement of said grinding wheel guard relative to saidgrinding wheel head is effected.

2. A grinding wheel guard device for a grinding machine as set forth inclaim 1, wherein said drive means further comprises a hand wheel keyedto said second shaft member for manually moving said grinding wheelguard.

3. A grinding wheel guard device for a grinding machine as set forth inclaim 1, wherein said drive means further comprises a reversible motoroperatively connected with said second shaft for automatically movingsaid grinding wheel guard to selectively open or 5 close said grindingwheel guard on said grinding wheel head.

4. A grinding wheel guard device for a grinding machine as set forth inclaim 3, further comprising a hand wheel keyed to said second shaftmember for manually moving said grinding wheel guard.

5. A grinding wheel guard device for a grinding

1. A grinding wheel guard device for a grinding machine characterized bya grinding wheel head rotatably supporting at least one grinding wheel,comprising: a first shaft member rotatably mounted on said grindingwheel head; a grinding wheel guard secured to said first shaft member;and drive means mounted on said grinding wheel head being operablyconnected with said first shaft member for moving said grinding wheelguard relative to said grinding wheel head; said drive means comprisinga worm wheel keyed to said first shaft member, a second shaft memberrotatably mounted on said grinding wheel head and a worm gear disposedon said second shaft member for rotation therewith being operablyengaged with said worm wheel for causing said first shaft membersupporting said grinding wheel guard to rotate, whereby pivotablemovement of said grinding wheel guard relative to said grinding wheelhead is effected.
 2. A grinding wheel guard device for a grindingmachine as set forth in claim 1, wherein said drive means furthercomprises a hand wheel keyed to said second shaft member for manuallymoving said grinding wheel guard.
 3. A grinding wheel guard device for agrinding machine as set forth in claim 1, wherein said drive meansfurther comprises a reversible motor operatively connected with saidsecond shaft for automatically moving said grinding wheel guard toselectively open or close said grinding wheel guard on said grindingwheel head.
 4. A grinding wheel guard device for a grinding machine asset forth in claim 3, further comprising a hand wheel keyed to saidsecond shaft member for manually moving said grinding wheel guard.
 5. Agrinding wheel guard device for a grinding machine as set forth in claim3, further comprising limit switches at preselected positions on saidgrinding wheel head in the path of movement of said grinding wheelguard, and means on said grinding wheel guard for engaging said limitswitches.
 6. A grinding wheel guard device for a grinding machine as setforth in claim 4, further comprising releasable clamping means forsecuring said grinding wheel guard in said closed position.